A man has been arrested in connection with a 500lb car bomb abandoned near a busy motorway in Northern Ireland.

The 26-year-old suspect is being questioned about the device left at the A1 bypass in Newry, Co Down, last Thursday.

He was detained in the Rostrevor area of Co Down and has been taken to Antrim police station for questioning.

The failed bomb attack has been blamed on dissident republicans opposed to the peace process.

On Wednesday night detectives investigating the dissident republican murder of Catholic police officer Ronan Kerr in Omagh, Co Tyrone, were given six more days to question two of three suspects being held.

Detectives later carried out a number of searches in the Newry, Warrenpoint and Rostrevor areas in relation to dissident republican activities and the abandoned motorway bomb.

A further search was carried out in the greater Belfast area.

No arrests were made but a number of items were removed for forensic examination.